position/sizeElement do not cancel effects unless new effects are starting

Any ongoing effects should be stopped (automatically completing their run) 
on the next call to position/sizeElement (with the same element).

The logic is wrong on these two functions in that they only cancel on the 
start of a new effect (and not without a specified effect).

Changed locally and also added return of EffectTimer object so that callers 
can stop the effect (completing it or not per the one argument to the stop 
method) without calling position/sizeElement again.

Original issue reported on code.google.com by dmark.ci...@gmail.com on 29 Apr 2010 at 8:29

pvdung / ourlibrary

position/sizeElement do not cancel effects unless new effects are starting #23